A refrigerating apparatus has thus far been known that includes a low-temperature side circuit in which a low-temperature circuit refrigerant circulates and a high-temperature side circuit in which a high-temperature circuit refrigerant circulates, the circuits being connected via a cascade condenser. In this type of refrigerating apparatus, when a low-temperature circuit compressor of the low-temperature side circuit stops working the refrigerant is warmed to a temperature close to the ambient temperature and thus gasified, and therefore the pressure in the low-temperature side circuit increases. Accordingly, in the case where the low-temperature circuit compressor is not operated for a long time the pressure in the low-temperature side circuit reaches the design pressure (maximum permissible pressure), which may provoke abnormal non-operation of operation or activation of a safety valve for discharging the refrigerant.
Accordingly, a refrigerating apparatus has been proposed that includes an expansion tank for preventing the pressure in the low-temperature side circuit from exceeding the design pressure, where the low-temperature circuit compressor having been not operated for a long time (see, for example, Patent Literature 1).